Lipid-conjugates are thought to inhibit the enzyme phospholipase A2 (PLA2, EC 3.1.1.4). Phospholipase A2 catalyzes the breakdown of phospholipids at the sn-2 position to produce a fatty acid and a lysophospholipid. The activity of this enzyme has been correlated with various cell functions, particularly with the production of lipid mediators such as eicosanoid production (prostaglandins, thromboxanes and leukotrienes), platelet activating factor and lysophospholipids. Lipid-conjugates may offer a wider scope of protection of cells and organisms from injurious agents and pathogenic processes, including the prevention and treatment of dermatologic conditions.
Dermatologic conditions are far more prevalent than once thought and cost an estimated $37.17 billion annually in the US, according to a comprehensive study jointly released in April 2005 by the American Academy of Dermatology Association and the Society for Investigative Dermatology. These estimates consider the costs of doctor visits, over-the-counter and prescription medicine costs and lost work productivity. The new study found that at any given time, one in every three people in the U.S. suffers from a skin disease—exceeding the prevalence of obesity, hypertension and cancer. Among the most economically burdensome skin disorders are skin ulcers and wounds, melanoma, nonmelanoma skin cancer, atopic dermatitis and acne, the cost of which totaled $22.46 billion in 2004. It is estimated that NIH research expenditures on skin diseases will total nearly $172 million in 2005.
Dermatitis, which is sometimes called eczema, is an inflammation reaction of the skin to various external and internal causes and is the most common among the skin diseases. Typical clinical features in acute stage dermatitis include swelling erythema, followed by the formation of papules and serous papules on the erythema. After the formation of vesicles in the skin, pustules form, followed by the erosion, crusting and desquamation of the skin. Only then does the skin begin to heal. When dermatitis turns chronic, thickening, lichenification and pigmentation of the skin all result and, in most cases, accompanied by itching. Histologically, dermatitis is characterized by swelling among epidermal cells (in a spongy state) during the acute stage. Contact dermatitis, atopic dermatitis, seborrheic dermatitis, etc. are included among recognized categories of dermatitis.
External application of a steroidal agent (ointment or the like) is the most effective therapy to date and no therapeutic method to replace it has yet been established. However, steroid preparations also cause a great variety of adverse reactions. There have been various reports on the side effects of steroid preparations and, in the case of agents for external use such as ointments, direct harmful effects such as the thinning, shrinking and flushing of the skin. The severe adverse reactions caused by steroid preparations used as remedies for dermatologic conditions have led to a demand in the medical field for safer pharmaceuticals which have fewer side effects.